Data centers are parts of buildings or facilities in which a large number of server computers are located. The dense packing of the server computers results in the generation of a large amount of heat in a localized area. The data center must be cooled in a reliable manner in order to avoid the shutting down of, or damage to, the server computer hardware. Shutting down of server computers due to heat overload can cause significant economic loss.
Accordingly, specialized cooling units have been developed for implementation directly in data centers. These specialized cooling units are sometimes known in the art as computer room air conditioning units (“CRACs”) or computer room air handling units. In this disclosure, air conditioning unit or CRAC will be understood to encompass any device used to effect cooling in a data center. CRACs have been employed as a result of the fact that the ordinary HVAC systems of buildings are not optimally configured to handle the concentrated head generated with data centers. Thus, CRACs are often used in connection with, but in addition to, the ordinary cooling units of a building employed for human comfort systems.
Many CRACs have simple, embedded controls that adjust the unit output based on factors such as sensed ambient air temperature. In some cases, CRACs have controllers that interact with the building automation system that controls or includes the building HVAC system, among other things.
While CRACs provide a solution to the need for enhanced cooling power within a data center having several server computers, there is nevertheless a danger of overheating, due to imbalanced loading of processing tasks within the data center, malfunction or inefficiency of a CRAC unit, or local conditions within the data center that affects the ability to cool certain servers or groups of servers. It is therefore desirable to reduce the risk of overheating or other malfunction of one or more processors in a data center. There is also a need to improve the efficiency in energy consumption in data centers attributable to cooling.